Method of removing organometallic compounds from liquid hydrocarbons

ABSTRACT

Organometallic compounds are separated from liquid hydrocarbons containing the same by contacting the liquid hydrocarbon first with a treating agent selected from the group consisting of silicon tetrachloride, cupric chloride, cupric bromide, iodine and iodine in combination with an acid and then with a suitable sorbent such as an activated charcoal. Both the initial and final contacting may be accomplished at any combination of temperature and pressure at which the hydrocarbon will remain liquid and at which all components used in the process will remain stable. Both the initial and final contacting may be accomplished in essentially any suitable fashion; however, the first treating agent will, generally, be used in combination with a suitable solvent and effecting the second contacting in a fixed bed of the sorbent is, generally, most convenient and effective.

United States Patent [1 1 Zimmerman [451 July 8,1975

[75] Inventor: Abraham A. Zimmerman, New

Providence, NJ.

[73] Assignee: Exxon Research and Engineering Company, Linden, NJ.

[22] Filed: Apr. 8, 1974 [21] Appl. No.: 458,668

[52] US. Cl 208/253; 208/251 R; 208/307; 208/278; 208/91; 208/295;208/296 [51] Int. Cl C10g 17/00 [58] Field of Search 208/253, 251 R,252, 99, 208/289, 290-295, 307, 278, 281, 91, 251, 296

[56] References Cited UNITED STATES PATENTS 1,769,794 7/1930 Leamon208/307 1,814,410 7/1931 Richter et al. 208/295 1,988,114 6/1935 Egloffet al. 208/287 2,060,291 11/1936 Egloff 208/296 2,063,517 12/1936Morrell et al.. 208/296 2,392,846 l/l946 Friedman 208/253 2,884,3694/1959 Mattox et al..... 208/251 R 3,785,968 1/1974 Whitehurst 208/2513,791,968 3/1974 Whitehurst et al. 208/251 3,838,043 9/1974 Crook et al208/253 R19,879 3/1936 Lachman 208/296 OTHER PUBLICATIONS OSRD No. 3018National Defense Research Committee of Scientific Research andDevelopment Primary ExaminerDelbert E. Gantz Assistant Examiner-JuanitaM. Nelson Attorney, Agent, or F irmWayne Hoover [5 7] ABSTRACTOrganometallic compounds are separated from liquid hydrocarbonscontaining the same by contacting the liquid hydrocarbon first with atreating agent selected from the group consisting of silicontetrachloride, cupric chloride, cupric bromide, iodine and iodine incombination with an acid and then with a suitable sorbent such as anactivated charcoal. Both the initial and final contacting may beaccomplished at any com bination of temperature and pressure at whichthe hydrocarbon will remain liquid and at which all components used inthe process will remain stable. Both the initial and final contactingmay be accomplished in essentially any suitable fashion; however, thefirst treating agent will, generally, be used in combination with asuitable solvent and effecting the second contacting in a fixed bed ofthe sorbent is, generally, most convenient and effective.

15 Claims, N0 Drawings METHOD OF REMOVING ORGANOMETALLIC COMPOUNDS FROMLIQUID HYDROCARBONS BACKGROUND OF THE INVENTION This invention relatesto a process for separating organometallic compounds from liquidhydrocarbons. More particularly, this invention relates to a process forseparating organo lead compounds from liquid hydrocarbons.

As is well known, there is an increasing public and governmentalinterest in eliminating or at least significantly reducing the amount oflead emitted to the atmosphere as the result of combustion of leadedfuels in internal combustion engines. In fact, recently passedlegislation does (or will) establish emission standards which can be metonly through the use of substantially lead-free fuels. The same orrelated legislation also creates specifications for such fuels and canimpose rather harsh sanctions against those which would market suchfuels but not meet the specifications therefor.

The production of lead-free of substantially lead-free fuels is, ofcourse, well within the ordinary skill of the art. Delivery of suchfuels to the consumer, however, cannot be as easily accomplished. Infact, past experience with both lead-free and low lead fuels hasindicated that intentional and/or inadvertent comingling of such fuelswith leaded fuels renders such ultimate delivery impossible, at least,in 100% of the cases. Such comingling could, of course, occur in thepipelines or transport tankers as well as in storage tanks at terminalsor retail outlets. The need, then, for a method, short of separatetransport and storage facilities, which would ensure the delivery of asubstantially lead-free fuel is readily apparent.

One such method which could be used is a separation method which wouldpermit separation of relatively minor amounts of lead from the fuelstored at a terminal or a retail outlet (after transport) or from thegasoline in a tanker or pipeline or delivery truck prior to transferinto a storage vessel. Indeed, several separation processes have,heretofore, been proposed for the separation of organo lead compoundsfrom gasoline. Generally, these have been two-step processes wherein theorgano lead compound is first converted to an insoluble or easilyabsorbed form and thereafter separated either by absorption, waterwashing, filtration and/or decanting. Often, the chemical conversion isaccomplished with a Lewis acid such as stannic chloride and theseparation effected with an adsorbent such as activated charcoal. Theseprior art methods have, however, been primarily concerned with theseparation of relatively high concentrations of lead (greater than 1gram lead per gallon of gasoline) from relatively small volumes ofgasoline and are not well suited to use for theseparation of relativelysmall concentrations of lead (less than 0.5 grams lead per gallon ofgasoline) from comparatively large volumes of gasoline. In this regard,it should be noted that separation rate was a relatively minorconsideration in the prior art processes with emphasis having beenplaced on separation capacity. In the present situation, emphasis mustbe placed on the absorption rate due to the large volumes which must betreated and separation capacity is a less significant factor.

In general, these prior art processes also result in an increased gumcontent in the treated gasoline. While this condition may, generally, betolerated with respect to relatively small volumes of gasoline, to beused in relatively inexpensive equipment having a relatively shortdesign life, it obviously cannot be tolerated in large volumes ofgasoline to be used in modern automobile engines. The need, then, for aseparation process suited to the treatment of large volumes of gasolinewithout increasing the gum content thereof should be readily apparent.

SUMMARY OF THE INVENTION It has now been found that the foregoing andother deficiencies of the prior art organo lead separation processes canbe avoided with the process of this invention and a process well suitedto the separation of relatively small concentrations of lead fromrelatively large volumes of liquid hydrocarbon provided thereby. It is,therefore, an object of this invention to provide an improved processfor separating organo lead compounds from liquid hydrocarbons. It isanother object of this invention to provide such a process wherein theseparation is accomplished at a relatively high rate. It is stillanother object of this invention to provide such a process which may beused without increasing the gum content of the liquid hydrocarbonssubjected to treatment. Still other objects and advantages will becomeapparent from the disclosure set forth hereinafter.

In accordance with the present invention, the foregoing and otherobjects and advantages are accomplished with a process wherein a liquidhydrocarbon containing one or more organo lead compounds is firstcontacted with one or more treating agents selected from the groupconsisting of silicon tetrachloride, iodine, iodine in combination withan acid, cupric chloride and cupric bromide and thereafter contactedwith a suitable sorbent. As is pointed out more fully hereinafter, it isessential that the selected treating agent be used in combination with asuitable solvent although the liquid hydrocarbon may, itself, satisfythis requirement in certain cases.

DETAILED DESCRIPTION OF THE INVENTION Broadly, the method of thisinvention can be used to separate or remove organo lead compounds fromany hydro carbon which might contain such organo lead compounds in adissolved form. The process may, then, be used to separate organo leadcompounds from normally gaseous hydrocarbons which have been made liquidas a result of increased pressure as well as solid or highly viscoushydrocarbons which had been made liquid as the result of increasedtemperature. The process is equally useful to separate organo leadcompounds from mixtures of such hydrocarbons as well as mixtures ofeither one or both of these types of hydrocarbon with normally liquidhydrocarbons. The process is, however, most useful for the separation oforgano lead compounds from mixtures of normally liquid hydrocarbons,which mixtures contain one or more gaseous hydrocarbons dissolvedtherein. Mixtures of this type include the leaded and unleaded fuelssuch as gasoline, jet fuel and kerosene. The method of this invention isparticularly useful for the separation of organo lead compounds fromconventional leaded gasolines as well as unleaded gasolines which may asa result of contamination contain relatively minor amounts of organolead compounds.

As indicated previously, the organo lead compounds will be separated byfirst contacting the liquid hydrocarbon containing the same with one ormore pretreating agents selected from the class consisting essentiallyof silicon tetrachloride, iodine, iodine in combination with an acid,cupric chloride and cupric bromide. Generally, the treating agentselected for use will first be dissolved in a suitable solvent and thencontacted with the liquid hydrocarbon in any suitable fashion which willinsure reasonably good contacting between the organo lead compound orcompounds and the pretreating agent. The use of a separate solvent isnot, however, essential to the method of the present invention,particularly, when the treating agent employed is either soluble in theliquid hydrocarbon or when the liquid hydrocarbon also contains one ormore constituents which is soluble therein and in which the selectedtreating agent is also soluble.

As used herein, then, in reference to the pretreating agent, therecitation suitable solvent means a material not only in which thepretreating agent is soluble at the concentration employed therein butone which is, itself, soluble in the liquid hydrocarbon at theconcentration in which it is added thereto. Also, the recitation as usedherein is intended to include only those materials which can beseparated from the liquid hydrocarbon after the pretreatment or which,if allowed to remain therein, will not adversely affect the quality orcharacter of the liquid hydrocarbon or detract from its use for itsintended purpose. Suitable solvents do, therefore, include both organicand inorganic materials which satisfy the dual solubility requirementheretofore noted. The organic solvents are, however, preferred, since,generally, these materials need not be separated from the liquidhydrocarbon after the pretreatment so as to preserve the character andquality thereof. Useful organic solvents include alcohols, ethers,ketones, and aromatic hydrocarbons such as benzene and xylene. Moreover,alcohols and particularly isopropyl alcohol, are particularly preferred.It should, however, be noted that alcohols will not generally be usedwith SiCl, due to undesirable reactions thereof.

As previously indicated, then, the selected pretreating agent or agentswill, generally, be dissolved in a suitable solvent before the same iscontacted with the liquid hydrocarbon containing the dissolved organolead compound or compounds. The actual concentra tion of pretreatingagent in solution is, however, not critical to the present inventionand, indeed, essentially any concentration consistent with theaforementioned solubility requirements can be used. Notwithstandingthis, however, and since organic solvents will preferably be usedwithout subsequent separation thereof, it is also preferred that thosesolvents permitting the higher concentrations of pretreating agents beused and that the solutions be used at the higher concentrations so asto minimize dilution of the liquid hydrocarbon being treated. Since thealcohols, and particularly the lower monohydric alcohols containing fromabout I to about 6 carbon atoms therein, yield solutions containing thehighest concentrations of pretreating agent or agents, these solventsare particularly preferred for all of the pretreating agents exceptSiCL, and isopropyl alcohol is the most preferred of this group ofsolvents. For SiCl the hydrocarbon solvents and particularly thearomatic hydrocarbon solvents such as xylene are particularly preferred.

Similarly, the amount of pretreating agent or agents added to thehydrocarbon is not critical, especially in these embodiments wherein asorbent, impregnated with a material capable of converting the dissolvedorgano lead compounds to a different, more easily separated form, isused. In this regard, and while the inventor does not wish to be boundby any particular theory, it is believed that the pretreating agentsuseful in this invention react with the organo lead compounds so as toform different lead compounds which are either insoluble (and thereforereadily separable) or which are more readily absorbed by thesorbentsused in the second step of the present invention. The amountactually used is, then, not critical since, in any case, some reductionwill be achieved at any concentration and, indeed, when an impregnatedsorbent is used, substantially complete separation of the lead compoundsis possible at any concentration. Nonetheless, the method of thisinvention is most effective when the amount of pretreating agentactually used is between about l and 20 times that which would berequired for a stoichiometric conversion to a monohalide derivative ofall organo lead contained in the liquid hydrocarbon subjected totreatment.

With respect to what would constitute a stoichiometric amount of ap'retreating agent, it should be noted that when iodine or silicontetrachloride are used as the pretreating agents and the organo leadcompounds are all of the tetralkyl variety, one mole of iodine orsilicon tetrachloride per mole of tetraalkyl lead compound would effecta stoichiometric conversion thereof. The molar amount of cupric chlorideand/or cupric bromide required, on the other hand, would be twice theamount of silicon tetrachloride required for a comparable conversion.Finally, the amount of iodine plus an acid required will depend upon theparticular acid used, and upon the molar ratio of iodine and acidactually employed. In this regard, it should be noted that any acidcontaining an anion which will displace an alkyl radical of thealkylated compound and thereby form a less soluble or more readilyabsorbed lead compound could be used in combination with the iodine.Acids containing the sulfate anion or anions derived from the halidegroup and, particularly hydrogen chloride, are, however, preferred. Inthis case, then, the molar ratio of iodine (1 to acid (l-ICl) will rangebetween about 0.1 and i 0.5 and the molar amount of iodine plus and acidrequired to effect a stoichiometric conversion will usually be the samemolar amount required for a corresponding conversion with silicontetrachloride.

in general, the pretreatment step of this invention will be accomplishedby contacting or mixing the lead containing hydrocarbon with pretreatingagent solution at a temperaturebetween about 30 and F., although higheror lower temperatures might be used in certain cases, with agitation orother means for providing the desired degree of mixing. Generally,conversion of the organo lead compounds will be accomplished within atime period of about 3 to about 40 minutes. Longer contacting periodsmay, however, be required for the conversion of some lead compounds.

In general, any of the absorbents known in the prior art to be usefulfor separating lead compounds from liq- -uid hydrocarbons can be used inthe absorption step of thepresent process. These include activatedcarbon, acid treated clays, silica gel, etc. Moreover, the ferricchlorideimpregnated activated carbons, disclosed in the inventorscopending application Ser. No. 405,124

which was filed Oct. 10, 1973, and the cupric chloride impregnatedactivated carbons, disclosed in the inventors copending application Ser.No. 458,669 which was filed of even date herewith, can be used.Activated carbons, either with or withouot an impregnated metal halide,will, generally, yield best, results and are therefore preferred.

In this regard, it has been discovered that only a limited number of thecommercially available activated carbons or charcoals can be used in theprocess of this invention to achieve the desired high degree ofseparation. Such activated carbons include those which are substantiallyamorphous; i.e., activated carbons which do not exhibit a graphiticstructure or at least only slightly so, and which have high oxygencontents, high pore volumes and relatively high surface areas per unitweight. It will, of course, be appreciated that the method of preparingthe activated carbon; i.e. preparation with or without chemicals, maynot have any significant effect on the performance thereof in theprocess of this invention and activated carbons prepared by any methodare considered equivalent so long as the properties thereof are withinthe ranges set forth hereinafter. One exception to this otherwisegeneral rule is, however, that preparation in the presence of arelatively strong acid such as hydrochloric acid or treatment with suchan acid after preparation will, generally, enhance performance. Careshould, however, be taken in such treatment to avoid acid concentrationssuffihigh to permit leaching thereof during the contacting process suchthat the acid number of the treated hydrocarbon is significantlyincreased.

As has been noted, supra, best results are achieved with the method ofthis invention when the activated carbons employed therein issubstantially amorphous. This does not, however, mean that the activatedcarbons must be completely free of crystalline structure. In fact, ithas been found that useful activated carbons may exhibit up to about wt.crystallinity or that the same may contain up to 20 wt. %-of carbonhaving a graphitic type structure. Such activated carbons are,therefore, considered to be within the meaning ofsubstantially amorphousas used herein. Also, the activated carbons which are useful in themethod of this invention will exhibit oxygen contents within the rangeof about 3 to about wt. total pore volumes within the range of about 0.5to about 1.5 ml/g; and surface areas within the range of about 200 toabout 1500 m /g.

At this point it should be noted that while any activated carbonexhibiting properties within the aforedescribed ranges is operable, bestresults are obtained with activated carbons containing minimal amounts;i.e. less than about 5 wt. of crystalline structure. Moreover, it shouldbe noted that when activated carbons having higher degrees ofcrystalline structures (within the range heretofore specified) are used,best results therewith will usually be obtained when there is also acorresponding increase in the oxygen content thereof as well as withincreased total pore volumes.

As will be readily apparent, the particle size of the activated carbonis not critical to the present invention. Indeed, the method would bequite operative with any reasonable particle size provided thatsatisfactory means for separating the impregnated activated carbon areused. In this regard, it should be noted that essentially any of .thefiltration-or centrifugation methods known in the prior art couldbe usedto separate particles too small to be separated with any other means ineither a batch or continuous operation. Similarly, any other means knownto be effective in separating solids from liquids could be employed toeffect the desired separation. It is, however, most expedient andeffective to carry out the method of the present invention in such a wayas to either eliminate or at least minimize the need for such solidseparation and to minimize contacting time. For this reason, it ispreferred to accomplish the liquid hydrocarbon-impregnated activatedcarbon contacting by passing the liquid hydrocarbon through a fixed bedof the impregnated, activated carbon. When this method is used, agranular type activated type carbon will be used and the particle sizewill, generally, range between about 0.01 and 0.15 inches.

When a ferric chloride impregnated activated carbon is used, the samewill preferably be prepared in the same manner as indicated in copendingapplication Ser. No. 405,124. As there indicated, any of the hydrousferric chlorides known in the art may be used for form an impregnatedactivated carbon useful in the method of the present invention, In thisregard, as is well known, the hydrous ferric chlorides may berepresented by the formula FeCl 'X O wherein X may be any one of severalnumbers including 5, 6 and 12. These compounds may, of course, bereadily prepared with methods well known in the prior art or the samemay be obtained commercially from sereral sources.

The ferric chloride impregnated activated carbon useful in the method ofthis invention will then be prepared by first dissolving a suitablehydrated ferric chloride in water and then combining the ferric chloridesolution with a suitable activated carbon. The concentration of ferricchloride in the aqueous solution as well as the amount of such solutionused in combination with the activated carbon is, of course, notcritical to the invention and a satisfactory impregnated product can beobtained over a relatively broad range of such conditions. Best results,however, will be obtained when the total concentration of hydrous ferricchloride in solution is sufficient to provide the desired concentrationof ferric chloride on the activated charcoal and when the total amountof solution employed is sufficient to insure good wetting of theactivated charoal, and hence, good distribution of the ferric chloridewithout providing a large excess of water which must later be removed.Generally, the aqueous hydrous ferric chloride solution and theactivated charoal will be contacted in such a manner as to insure gooddistribution of the ferric chloride over the activated charcoal. Thiscan, of course, be readily accomplished with any of the well knownmixing techniques. After the ferric chloride solution and the activatedcarbon have been contacted for a sufficient period of time, excess waterwill be removed by drying. Again, this can be accomplished with methodswell known in the prior art such as by drying at an elevated temperaturein an oven and/or by contacting the impregnated activated carbon with aninert stripping gas such as nitrogen or air. It will, of course, beappreciated that the drying time and/or conditions can be controlledsuch that the resulting impregnated activated carbon may contain anydesired concentration of water within the pores thereof.

Generally, a satisfactory ferric chloride-impregnated activated carboncan be prepared by first forming an aqueous solution of hydrous ferricchloride containing between about 5 and 15 wt. ferric chloride (on awater-free basis) and thereafter contacting between about 1 and 2milliliters of this solution per gram of activated carbon (on awater-free basis). This contacting can be accomplished at anytemperature and pressure at which the hydrous ferric chloride remains insolution and at which the solution remains liquid. Generally, thecontacting will be continued for a period of time sufficient to permit acomplete wetting of the activated carbon. Following this contacting, thewetted activated carbon will be dried so as to remove at least 50 wt. ofthe total water; i.e., the water derived from the hydrous ferricchloride as well as any that might be contained in the activated carbonand the water used to form the solution, therefrom and most generally soas to remove between about 65 and 85 wt. of such total water. Generally,the ferric chloride impregnated activated carbon which may be used inthe method of this invention will contain between about 5 and wt. FeCl(on a water-free basis), between about 50 and 93 wt. activated carbonson a water-free basis, and between about 2 and wt. water.

When a copper chloride impregnated activated carbon is employed in themethod of this invention, the same will be prepared in the mannerdisclosed in copending application Ser. No. 458,669. As there indicated,the impregnated activated carbon useful in the method of this inventionmay be prepared by first dissolving a cupric chloride in a suitablesolvent and then combining the cupric chloride solution with a suitableactivated carbon. The concentration of cupric chloride in the solutionas well as the amount of such solution used in combination with theactivated carbon is, of course, not critical to the invention and asatisfactory impregnated product can be obtained over a relatively broadrange of such conditions. Best results, however, will be obtained whenthe total concentration of cupric chloride in solution is sufficient toprovide the desired concentration of cupric chloride on the activatedcharcoal and when the total amount of solution employed is sufficient toinsure good wetting of the activated charcoal, and hence, gooddistribution of the cupric chloride without providing a large excess ofsolvent which must later be removed. Generally, the cupric chloridesolution and the activated charcoal will be contacted in such a manneras to insure good distribution of the cupric chloride over the activatedcharcoal. This can, of course, be readily accomplished with any of thewell known mixing techniques. After the cupric chloride solution and theactivated carbon have been contacted for a sufficient period of time,excess solvent will be removed by drying. Again, this can beaccomplished with methods well known in the prior art such as by dryingat an elevated temperature in an oven and- /or by contacting theimpregnated activated carbon with an inert stripping gas such asnitrogen or air. It will, or course, be appreciated that the drying timeand- /or conditions can be controlled such that the resultingimpregnated activated carbon may contain any desired concentration ofsolvent within the pores thereof.

In the broadest embodiment of this invention, organo lead compounds willbe separated from liquid hydrocarbons by first contacting a liquidhydrocarbon containing one or more organo lead compounds with apretreating agent selected from the group consisting of silicatetrachloride, iodine, iodine plus an acid, cupric chloride and cupricbromide and thereafter contacting the pretreated liquid hydrocarbon witha suitable sorbent. The desired contacting in both steps may beaccomplished either in a batch, semi-batch or continuous operation andas indicated, supra, essentially any absorbent particle size may beused. Where the particle size is relatively small, however, it will benecessary to separate the impregnated activated carbon from the liquidhydrocarbon with a suitable method such as filtration or centrifugation.Where the particle size is somewhat larger, however, separation might beaccomplished by settling followed by decanting or again with methodssuch as filtration and centrifugation. Where the particle size issufficiently large and particularly in the range previously specified,it will be possible to effect the contacting in a fixed bed of theimpregnated activated carbon, in which case the liquid hydrocarbon will,effectively, be separated from the impregnated activated carbon afterthe desired contacting has been accomplished.

Broadly, the method of this invention may be used to treat liquidhydrocarbons containing essentially any possible concentration ofdissolved organo lead compounds. Generally, however, the method will beused to treat hydrocarbons containing less than 5 grams of dissolvedlead per gallon and the same will be most effective for treating liquidhydrocarbons having less than 0.5 grams of dissolved lead per gallon. Inthis regard, it should be noted that the effective life of the absorbentwill depend upon the amount of lead and other components actuallyseparated therewith and as is pointed out more fully, hereinafter, themethod of this invention will be most effective when the liquidhydrocarbon is pretreated with at least a stoichiometric quantity ofpretreating agent required for conversion of the organo lead compound toa monohalide derivative. The advantages derived from such pretreatmentare, of course, most significant from a standpoint of overall separationand sorbent life.

In general, separation of the organo lead compounds will be accomplishedat a satisfactory rate when sufficient sorbent is used to providebetween about 10 and 200 grams of sorbent, on a water-free basis, pergram of dissolved lead in the liquid hydrocarbon subjected totreatmentJMoreover, the rate of absorption will remain satisfactory, atleast in those cases where the hydrocarbon does not contain othercomponents which might interfere with the lead separation, until theamount of lead absorbed by the sorbent is somewhere within the range ofabout 0.005 to 0.10 grams of lead per gram of sorbent (on a water-freebasis). As will be readily apparent, then, in a batch operationseparation can be effected by adding a fixed amount of the pretreatingagent and asorbent to a fixed volume of liquid hydrocarbon, the amountadded being determined by the amount of lead to be separated from theliquid hydrocarbon and the amount, if any, of other components whichmight also be reacted or absorbed or otherwise decrease the capacity ofthe pretreating agent and/or sorbent. In a semi-batch or continuousoperation, on the other hand, contacting with a pretreating agentfollowed by contacting with a fixed amount of sorbent could be continueduntil the concentration of lead in the treated hydrocarbon exceeds thedesired concentrations.

It will, of course, be appreciated that good contacting between theliquid hydrocarbon and the pretreating agent and the sorbent isimportant to a complete separation. Such contacting could, of course, beachieved by shaking, agitation or the like or the same might be achievedby passing the liquid hydrocarbon first through a mixing chamber or anagitated vessel and then through a fixed bed of sorbent. In this regard,it should be noted that sufficient contacting with the sorbent will beaccomplished in a fixed bed when the liquid hydrocarbon is passedthrough a bed of sorbent having a particle size within the rangeheretofore specified at a rate within the range of about 2 to aboutgallons per hour per lb. of sorbent.

In general, the contacting between the pretreated liquid hydrocarbon andthe sorbent will be accomplished at a temperature between about 30 and120F. and a contacting time within the range of about 1 and about 5minutes will be sufficient to effect the desired separation using thefixed bed procedure. The fact that the method of this invention can beoperated at relatively low temperatures does, of course, offer atremendous advantage since it is contemplated that the same might beused at retail outlets which would not offer convenient heatingfacilities. The process cannot, however, be operated at extremely lowtemperatures since the reaction rate and rate of diffusion into thepores of the activated carbon would become too slow.

As indicated, supra, the method of this invention can be effectivelyused to separate relatively large lead concentrations from liquidhydrocarbons. Large concentrations will, however, significantly reducethe useful life of the sorbent. This in turn would result in frequentreplacement or regeneration thereof. For this reason, then, it may bedesirable to use two or more separate pretreatments, when treating aliquid hydrocarbon containing more than about 0.5 g. Pb/gal., beforecontacting the pretreated liquid with sorbent so as to maximize the lifeof the sorbent. In this embodiment of the invention, each of theseparate pretreatments would be completed in the same manner and,generally, each pretreatment would be followed by a filtration so as toremove suspended solids. When the lead concentration is below about 0.5grams per gallon and preferably below about 0.3 grams per gallon, asingle pretreatment followed by contacting with a suitable sorbent will,generally, yield 21 treated hydrocarbon having less than 0.05 g Pb/gal.thereof.

With respect to the pretreatment of the lead containing hydrocarbon,cupric chloride has been found most advantageous as the pretreatingagent. This and the other pretreating agents will generally be used inaccordance with techniques known or obvious from related processes andsuch use need not be described in detail herein. Nevertheless, it shouldbe noted that any one of these compounds or a mixture of any one or morethereof will, generally, be dissolved in a suitable solvent and combinedwith the liquid hydrocarbon containing dissolved lead at a temperaturebetween about 30 and about lF. for a period of time sufficient to effectthe desired conversion of the soluble lead compounds. The conversionproducts thus formed will then be separated with a suitable method suchas water washing, decanting, filtration and/or centrifugation. It'will,of course, be appreciated that the amount of pretreating agent employedis not critical, but the amount actually used will generally exceed thestoichiometric amount required for complete conversion of the solublelead compounds present in the treated hydrocarbons to a monohalidederivative and may range as high as 20 times that amount.

In this regard, it should, however, be noted that when large excessesare used, it may be necessary to subsequently separate the excesspretreating agent from the liquid hydrocarbon and, indeed, this will,generally, be accomplished via filtration followed by absorption withany of the sorbents herein indicated as useful. Such absorption may,however, reduce the effective capacity of the sorbent and should,therefore, be minimized. For these reasons, then, it is preferred thatthe amount of pretreating agent actually used be a minimum which isconsistent with effective separation. Generally, this will be within therange of about 2 to about 10 times the stoichiometric amount requiredfor the conversion of a tetraalkyl to a monohalide derivative, and, mostpreferably, the pretreating agent will be used in an amount within therange of about 3 to about 6 times this stoichiometric amount.

As indicated supra, the method of the present invention can be used toseparate dissolved organo lead compounds from any liquid hydrocarbon.The process is particularly useful, however, for the separation oftetraalkyl lead compounds such as tetraethyl lead and tetramethyl leadfrom mixtures of liquid hydrocarbons such as gasoline, jet fuel andkerosene. The method of this invention is particularly useful for theseparation of minor concentrations of such lead compounds from liquidhydrocarbon mixtures to be offered and sold as unleaded gasolines.

PREFERRED EMBODIMENT In a preferred embodiment, anhydrous cupricchloride dissolved in isopropyl alcohol at a concentration within therange from about I to about 5 wt. will be used in combination with anactivated carbon which is substantially free of graphitic type carbon(less than about 5 wt to separate tetraalkyl leads, and particularlytetraethyl and tetramethyl leads or equilibrated mixes thereof fromgasoline. The activated carbon, in addition to being substantially freeof graphitic type carbon, will exhibit a pore volume within the rangefrom about 0.8 to about 1.2 ml/g., an oxygen content within the rangefrom about 5 to about 20 wt. and a surface area between about 500 and1000 m /g.

In the preferred embodiment, the lead concentration in the gasoline willbe less than 0.5 g./gallon and in a most .preferred embodiment the leadconcentration will be less than 0.3 g/gallon. Moreover and as indicated,supra, the lead containing gaoline will first be pretreated bycontacting the same with a solution of cupric chloride in isopropanol.The pretreatment will be accomplished by mixing the pretreating agentwith the leaded gasoline in an amount ranging between about 2 and aboutl0,times that required for stoichiometric conversion of the tetraalkyllead contained therein and then subjecting the mixture to agitation. Thepretreatment will be accomplished at a temperature between about 40 andF. under conditions of intimate contacting for a period of time betweenabout 5 and 20 minutes. The pretreated gasoline will then be filteredand the filtrate then contacted with an activated carbon exhibitingproperties within the range heretofore specified. The contacting withthe activated carbon will be accomplished in a fixed bed thereof, theactivated carbon having an average particle size within the range ofabout 0.015 to about 0.06 inches and at a flow rate between about 4 andabout 8 gallons (gasoline) per hour per pound of impregnated activatedcarbon. Generally,

the actual contacting time between the filtrate and carbon will bewithin the range of about 1 to about 3 minutes.

It is believed that the present invention will become even more apparentfrom the following examples which illustrate the broadest embodimentthereof, a preferred embodiment thereof and a most preferred embodimentthereof. These examples are not, however, intended to limit theinvention in any way.

EXAMPLE 1 Two liters of gasoline containing 0.18 g. Pb/gal. thereof, butno light or heavy cat naphthas, was combined with 8 ml of an isopropanolsolution of CuCl containing 3.8 wt. CuCl The isopropanol solution wasadded to small batches of the gasoline with stirring such that theaverage contact time was about /2 hour. The contacting was accomplishedat a temperature of 75F. The thus treated mixture was then filtered bypassing the same through a filter to separate any precipitated solids.The filtrate was then passed through a fixed bed of activated carbon (10g) such that the average contact time was about 2 minutes. The activatedcarbon had a total pore volume of 1.1 ml/g, contained 16.5 wt. O 5 wt. HO, exhibited a surface area of 640 m lg and was substantially amorphousor nongraphitic. The particle size of the activated carbon was such thatthe same passed through a mesh (U.S.) screen but was retained on a 40mesh (U.S.) screen. After completion of the pretreatment and adsorptionsteps, the treated gasoline was filtered so as to separate any suspendedsolids therein. The treated gasoline was, then, analyzed for leadcontent and found to contain 0.02 g Pb/gal.

EXAMPLE 2 Two liters of gasoline identical with that used in Ex ample lwas first combined with 12 grams of a solution containing 1.5 wt. l and1.8 wt. HCl at a temperature of 75F., in small batches, and agitatedbriefly with an average contact time of about 30 minutes. Following thispretreatment the gasoline was filtered to separate suspended solids andpassed through a bed of 10 g. of activated carbon identical to that usedin Example 1 at a temperature of 75F. such that the average contactingtime was about 2 minutes. Again, the contacting was accomplished bypassing the gasoline through a fixed bed of the activated carbon and thetreated gasoline was filtered thereafter to separate any suspendedsolids remaining therein. Following this contacting, the treatedgasoline was then analyzed for dissolved lead content As a result ofthese tests, it was found that the same contained 0.04 grams Pb/gallon.

EXAMPLE 3 Two additional liters of gasoline identical with that used inExamples 1 and 2 was first combined with 5.4 grams of a benzene solutioncontaining 12.5 wt. silicon tetrachloride at a temperature of 75F. insmall batches, and agitated briefly with an average contact time of 30minutes. Following this pretreatment the 2 liters of gasoline werefiltered and then passed over 10 g. of activated carbon identical tothat used in Exampics 1 and 2 at a temperature of 75F. such that theaverage contacting time was about 2 minutes. The treated gasoline wasthen filtered. Following this treatment, the

gasoline was analyzed for lead content and found to contain 0.03 gramsPb/gallon.

EXAMPLE 4 Two liters of gasoline containing 0.07 g. Pb/gal. thereof and25 wt. light and heavy cat naphthas was combined in small batches with12 ml. of an isopropanol solution of CuCl containing 2.2 wt. CuCl andthe resulting mixture subjected briefly to mild agitation at atemperature of F. The thus treated mixture was then filtered by passingthe same through a 5;]. filter to separate any precipitated solids. Thefiltrate was then passed through a fixed bed of activated carbon (10 g)such that the average contact time was about 2 minutes. The activatedcarbon had a total pore volume of 1.1 ml/g, contained 16.5 wt. O 5 wt. HO, exhibited a surface area of 640 m /g was amorphous or nongraphitic.The particle size of the activated carbon was such that the same passedthrough a 20 mesh (U.S.) screen but retained on a 40 mesh (U.S.) screen.After completion of the pretreatment and absorption steps, the treatedgasoline was filtered so as to separate any suspended solids therein.The treated gasoline was, then, analyzed for lead content and found tocontain 0.02 g Pb/gal.

EXAMPLE 5 Two liters of gasoline identical with that used in Example 4was first combined with 12 ml of a solution containing 2 wt. l and 1 wt.HCl at a temperature of 75F. and briefly agitated. Following thispretreatment the gasoline was filtered to separate suspended solids andpassed through a bed of 10 g activated carbon identical to that used inExample 4 at a temperature of 75F. such that the average contacting timewas about 2 minutes. Again, the contacting was accornplished by passingthe gasoline through a fixed bed of the activated carbon and the treatedgasoline was filtered thereafter to separate any suspended solids remaining therein. Following this contacting, the treated gasoline wasthen analyzed for dissolving lead content. As a result of these tests,it was found that the same contained .0l grams Pb/gallon."

EXAMPLE 6 Two additional liters of gasoline identical with that used inExample 4 was first combined with 5 ml of a xylene solution containing 7wt. silicon tetrachloride at a temperature of 75F. and briefly agitated.Following this pretreatment the 2 liters of gasoline was filtered andthen passed over 10 g of activated carbon identical to that used inExample 4 at a temperature of 75F. such that the average contacting timewas about 2 minutes. The treated'gasoline was then filtered. Followingthis treatment, the gasoline was analyzed for lead content and found tocontain 0.015 grams Pb/gallon.

EXAMPLE 7 Four liters of gasoline containing 0.09 g. Pb/gal. thereof and25% light and heavy cat naphthas was combined with 12 ml of anisopropanol solution of CuCl containing 2.5 wt. CuCl and the resultingmixture subjected to mild agitation as described in Example 1.

age contact time was about 2 minutes. The activated carbon had a totalpore volume of 1.1 ml/g, contained 16.5 wt. O 5 wt. H O, exhibited asurface area of 640 m /g and was amorphous or non-graphitic. Theparticle size of the activated carbon was such that the same passedthrough a 20 mesh (U.S.) screen but was retained on a 40 mesh (U.S.)screen. After completion of the pretreatment and absorption steps, thecompletion of the pretreatment and absorption steps, the treatedgasoline was filtered so as to separate any suspended solids therein.The treated gasoline was, then, analyzed for lead content and found tocontain 0.03 g Pb/gal.

EXAMPLE 8 Two liters of gasoline containing 0.18 g. Pb/gal. thereof butno light or heavy cat naphthas was combined with 16 ml of an isopropanolsolution of CuCl containing 3.8 wt. CuC1 and the resulting mixturesubjected to mild agitation as described in Example l. The thus treatedmixture was then filtered by passing the same through a Su filter toseparate any precipitated solids. The filtrate was then passed through afixed bed of activated carbon (.10 g) such that the average contact timewas about 2 minutes. The activated carbon had a total pore volume of 1.1ml/g. contained 16.5 wt. O 5 wt. H O, exhibited a surface area of 640 m/g and was amorphous or non-graphitic. The particle size of theactivated carbon was such that the same passed through a 20 mesh (U.S.)screen but was retained on a 40 mesh (U.S.) screen. After completion ofthe pretreatment and absorption steps, the treated gasoline was filteredso as to separate any suspended solids therein. The treated gasolinewas, then, analyzed for lead content and found to contain .01 g Pb/gal.

EXAMPLE 9 Four liters of gasoline containing 0.08 g. Pb/gal. thereof and25 Wt. light and heavy cat naphthas was combined with 24 ml of anisopropanol solution of 'CuCl '2H O containing 3 wt. CuC1 -2H O and theresulting mixture subjected to mild agitation in the same manner and atthe same conditions used in Example 1. The thus treated mixture was thenfiltered by passing the same through a 5p. filter to separate anyprecipitated solids. The filtrate was then passed through a fixed bed ofactivated carbon (10 g) identical that used in Example 1 such that theaverage contact time was about 1 minute. The thus treated gasolinecontained 0.06 g. Pb/gal.

EXAMPLE 10 An activated carbon impregnated with hydrous cupric chloridewas prepared by first dissolving 6.0 gram of CuCl- '2H O in 3.0 grams ofwater and 30.0 g. of methanol and then combining this solution with 50.0grams of granular activated carbon containing 5 wt. water. The particlesize of the granular carbon was such that the same all passed througha20 mesh (U.S.) screen and was retained on a 40 mesh (U.S.) screen. Theactivated carbon had a total pore volume of 1.1 ml/g., contained 16.5%oxygemhad a surface area of 640 m /g and was essentially amorphous ornongraphitic. The aqeuous methanolic cupric chloride solution and theactivated carbon were combined at a temperature of 75F. and the combinedmixture was stirred until the activated carbon'was throughly wetted.

The'combined mixture was then dried with nitrogen gas at a-temperatureof F. for a period of 2.5 hours. The resulting activated carboncontained 8 wt. CuCl 1.5 wt. methanol, 8.5 wt. H Oand 82% carbon. Tengrams of the impregnated activated carbon thus prepared were placed in afixed bed and contacted with four liters of gasoline containing 0.09grams Pb/gallon at 75F., such that the average contact time was about 1minute.

During the contacting, the flow of gasoline was sufficient as to assurethe desired degree of contacting between the lead and the activatedcarbon. After completion of the contacting, the treated gasoline wasfiltered to separate any suspended solids remaining therein. The treatedgasoline was then analyzed and found to contain 0.035 grams Pb/gallon.

EXAMPLE 1 1 Four liters of gasoline identical with that used in Example10 was first contacted with 0.5 grams cupric chloride (2% solution inisopropanol) at a temperature of 75F. for an average of 30 minutes insmall batches. In this Example, the gasoline was initially stirredduring this contacting period. Following this pretreatment the gasolinewas filtered to separate suspended solids and passed through a bedcomprising 10 grams of the hydrous cupric chloride impregnated activatedcarbon prepared in Example 10 at a temperature of 75F. Again, thecontacting was accomplished by passing the gasoline through a fixed bedof the sorbentand the treated gasoline was filtered thereafter toseparate any suspended solids remaining therein. Following thiscontacting, the treated gasoline was then analyzed for dissolved leadcontent. As result of these tests, it was found that the same contained0.015 grams Pb/gallon.

EXAMPLE 12 Two liters of gasoline containing 0.1 l g. of an equilibratedmix of tetraethyl lead and tetramethyl lead/gal. thereof, but no lightor heavy cat naphthas, was combined in small batches with 8 m] of anisopropanol solution of CuCl; containing 2 wt. CuC1 and the resultingmixture subjected, briefly, to mild agitation at a temperature of 75F.The thus treated mixture was then filtered by passing the same through a5 p. filter to separate any precipitated solids. The filtrate was thenpassed througha fixed bed of activated carbon (10 g) such that theaverage contact time was about 2 minutes. The activated carbon had atotal pore volume of 1.1 ml/g, contained 16.5 wt. O 5 wt. H O, exhibiteda surface area of 640 m /g and was amorphous or non-graphitic. Theparticle size of the activated carbon was such that, the same passedthrough a 20 mesh (U.S.) screen but was retained on a 40 mesh (U.S.)screen. After completion of the pretreatment and absorption steps, thetreated gasoline was filtered so as to separate any suspended solidstherein. The treated gasoline was, then, analyzed for lead content andfound to contain 0.05 g. Pb/gal.

EXAMPLE 13 Two liters of gasoline containing 0.1 l g. tetramethyllead/gal. thereof, but no light or heavy cat naphthas, was combined insmall batches with 10 ml of an aqueous isopropanol solution of 1 and HClcontaining 2 wt. l and 1 wt. HCl and the resulting mixture subjectedbriefly to mild agitation at a temperature of 75F. The thus treatedmixture was then filtered by passing the same through a p. filter toseparate any precipitated solids. The filtrate was then passed through afixed bed of ferric chloride impregnated activated carbon g) such thatthe average contact time was about 2 minutes. The activated carbon had atotal pore volume of 1.1 m lg. contained 16.5 wt. O 5 wt. H O, exhibiteda surface area of 640 m /g and was amorphous or non-graphitic. Itcontained 13 ferric chloride and 19% H O. The particle size of theimpregnated activated carbon was such that the same passed through a 20mesh (U.S.) screen but was retained on a 40 mesh (U.S.) screen. Aftercompletion of the pretreatment and absorption steps, the treatedgasoline was filtered so as to separate any suspended solids therein.The treated gasoline was, then, analyzed for lead content and found tocontain 0.02 g. Pb/gal.

EXAMPLE 14 Four liters of gasoline identical to that used in Example 9were contacted with 24 ml of an isopropanol solution containing 2.5 wt.CuCl in the same manner and under the same conditions as were used inExample 1. The pretreated gasolin was then filtered and passed over 10g. of activated carbon identical to that used in Example 1. The treatedgasoline contained 0.03 g. Pb/gal.

EXAMPLE Example 14 was repeated except that the gasoline used was firstpredried with silica gel so as to remove of the H 0 originally presenttherein. The treated gasoline from this Example, however, contained only0.024 g. Pb/gal. The results obtained in Examples 9, 14 and 15 thussuggest that improved results are obtained by reducing the water contentof the system.

EXAMPLE 16 The run of Example 14 was repeated except that 20 ml of anisopropanol solution containing 3 wt. CuBr was substituted for the 24 mlof CuCl solution. The thus treated gasoline contained 0.04 g Pb/gal.

EXAMPLE 17 Two liters of gasoline identical to that used in Example lwere pretreated with 7 ml of a benzene solution containing 3 wt. 1 insubstantially the same manner and at the same conditions described inExample 1. The pretreated gasoline was then filtered and passed over anactivated carbon bed identical to that used in Example 1 and at the sameconditions used therein. The thus treated gasoline contained 0.05 gPb/gal.

As will be readily apparent from the foregoing Examples, the method ofthe present invention is effective in separating tetraalkyl leadcompounds from gasoline. As will also be readily apparent, the method ofthis invention is effective over a relatively broad range of leadconcentrations.

While the present invention has been described and illustrated byreference to particularly preferred embodiments thereof, it will beappreciated that the same lends itself to several variations which wouldbe obvious to those of ordinary skill in the art. Reference should,therefore, be made solely to the appended claims to determine the scopeof the present invention.

Having thus described and illustrated the present invention what isclaimed is:

l. A method for separating an organolead compound from liquidhydrocarbons comprising the steps of first contacting a liquidhydrocarbon having an organolead compound dissolved therein with apretreating agent selected from the group consisting of silicontetrachloride, iodine, cupric chloride and cupric bromide and thereaftercontacting the pretreated hydrocarbon with an adsorbent useful forseparating lead compounds from liquid hydrocarbons selected from thegroup consisting of activated carbon, acid treated clays and silicagels, and then recovering a liquid hydrocarbon having a reduceddissolved lead content therein.

2. The method of claim 1 wherein the pretreating agent is firstdissolved in a suitable solvent and thereafter combined with said liquidhydrocarbon.

3. The method of claim 2 wherein the adsorbent is an activated carbonwhich is substantially amorphous and has an oxygen content within therange of about 3 to about 25 wt.

4. The method of claim 3 wherein said activated carbon contains lessthan about 5 wt. crystalline structure carbon; has an oxygen contentwithin the range of about 10 to about 20 wt. has a total pore volumewithin the range of about 0.8 to about 1.2 ml/g; and exhibits a surfacearea within the range of about 200 to.

about 1000 m /g.

5. The method of claim 2 wherein the contacting with said pretreatingagent is accomplished at a temperature between about 30 and about F.

6. The method of claim 2 wherein the contacting with the adsorbent isaccomplished in a fixed bed and is continued for a period of timebetween about 1 and about 5 minutes.

7. The method of claim 2, wherein the liquid hydrocarbon contains lessthan about 0.5 g Pb/gallon.

8. A method for separating a dissolved organo lead compound from aliquid hydrocarbon comprising:

1. first contacting a liquid hydrocarbon containing a dissolved organolead compound therein with a pretreating agent selected from the groupconsisting of silicon tetrachloride, iodine, cupric chloride and cupricbromide and mixtures thereof;

2. thereafter contacting said liquid hydrocarbon with an activatedcarbon; and

3. recovering a liquid hydrocarbon having a reduced dissolved leadcontent therein.

9. The process of claim 8 wherein the amount of pretreating agent usedis between about 1 and about 20 times the stoichiometric amount requiredto convert all of the dissolved lead contained in the liquid hydrocarbonto a monohalide derivative.

10. The method of claim 8 wherein said liquid hydrocarbon is firstcontacted with said treating agent at a temperature within the range ofabout 30 and about 120F. and thereafter contacted with an activatedcarbon at a temperature between about 30 and about 120F.

11. The method of claim 10 wherein said liquid hydrocarbon is filteredafter being contacted with said pretreating agent and before the same iscontacted with said activated carbon.

12. The method of claim 11 wherein the activated carbon is substantiallyamorphous and has an oxygen content within the range of about 3 to about25 wt.

13. The method of claim 11 wherein said activated carbon contains lessthan about 5 wt. crystalline structure carbon; has an oxygen contentwithin the range of about 10 to about 20 wt. has a total pore hol beforebeing combined with said liquid hydrocarvolume within the range of about0.8 to about 1.2 ml/g; hon

and exhibitsa surface area within the range of about to about 1000 mzlg.15. The method of claim 14 wherein said lower alco- 14; The method ofclaim 8 wherein said pretreating is isopropyl alcoholagent is CuCl andthe same is dissolved in a lower alco-

1. A METHOD FOR SEPARATING AN ORGANOLEAD COMPOUND FROM LIQUIDHYDROCARBONS COMPRISING THE STEPS OF FIRST CONTACTING A LIQUIDHYDROCARBON HAVING AN ORGANOLEAD COMPOUND DISSOLVED THEREIN WITH APRETREATING AGENT SELECTED FROM THE GROUP CONSISTING OF SILICONTETRACHLORIDE, IODINE, CUPRIC CHLORIDE AND CUPRIC BROMIDE AND THEREAFTERCONTACTING THE PRETREATED HYDRCARBON WITH AN ADSORBENT USEFUL FORSEPARATING LEAD COMPOUNDS FROM LIQUID HYDROCARBONS SELECTED FROM THEGROUP CONSISTING OF ACTIVATED CARBON, ACID TREATED CLAYS AND SILICAGELS, AND THEN RECOVERING A LIQUID HYDROCARBON HAVING A REDUCEDDISSOLVED LEAD CONTENT THEREIN.
 2. The method of claim 1 wherein thepretreating agent is first dissolved in a suitable solvent andthereafter combined with said liquid hydrocarbon.
 2. thereaftercontacting said liquid hydrocarbon with an activated carbon; and 3.recovering a liquid hydrocarbon having a reduced dissolved lead contenttherein.
 3. The method of claim 2 wherein the adsorbent is an activatedcarbon which is substantially amorphous and has an oxygen content withinthe range of about 3 to about 25 wt. %.
 4. The method of claim 3 whereinsaid activated carbon contains less than about 5 wt. % crystallinestructure carbon; has an oxygen content within the range of about 10 toabout 20 wt. %, has a total pore volume within the range of about 0.8 toabout 1.2 ml/g; and exhibits a surface area within the range of about200 to about 1000 m2/g.
 5. The method of claim 2 wherein the contactingwith said pretreating agent is accomplished at a temperature betweenabout 30* and about 120*F.
 6. The method of claim 2 wherein thecontacting with the adsorbent is accomplished in a fixed bed and iscontinued for a period of time between about 1 and about 5 minutes. 7.The method of claim 2, wherein the liquid hydrocarbon contains less thanabout 0.5 g Pb/gallon.
 8. A method for separating a dissolved organolead compound from a liquid hydrocarbon comprising:
 9. The process ofclaim 8 wherein the amount of pretreating agent used is between about 1and about 20 times the stoichiometric amount required to convert all ofthe dissolved lead contained in the liquid hydrocarbon to a monohalidederivative.
 10. The method of claim 8 wherein said liquid hydrocarbon isfirst contacted with said treating agent at a temperature within therange of about 30* and about 120*F. and thereafter contacted with anactivated carbon at a temperature between about 30* and about 120*F. 11.The method of claim 10 wherein said liquid hydrocarbon is filtered afterbeing contacted with said pretreating agent and before the same iscontacted with said activated carbon.
 12. The method of claim 11 whereinthe activated carbon is substantially amorphous and has an oxygencontent within the range of about 3 to about 25 wt. %.
 13. The method ofclaim 11 wherein said activated carbon contains less than about 5 wt. %crystalline structure carbon; has an oxygen content within the range ofabout 10 to about 20 wt. %; has a total pore volume within the range ofabout 0.8 to about 1.2 ml/g; and exhibits a surface area within therange of about 500 to about 1000 m2/g.
 14. The method of claim 8 whereinsaid pretreating agent is CuCl2 and the same is dissolved in a loweralcohol before being combined with said liquid hydrocarbon.
 15. Themethod of claim 14 wherein said lower alcohol is isopropyl alcohol.